Field of the Embodiments of the Present Disclosure
Embodiments of the present disclosure relate generally to audio signal processing and, more specifically, to an approach for partially preserving music in the presence of intelligible speech.
Description of the Related Art
Headphones, earphones, earbuds, and other personal listening devices are commonly used by individuals who desire to listen to a particular type of audio source, such as music, speech, or movie soundtracks, without disturbing other people in the nearby vicinity. These types of audio sources are referred to herein as “entertainment” signals, and each is typically characterized as an audio signal that is present over a sustained period of time. Typically, these personal listening devices include an audio plug for insertion into an audio output of an audio playback device. The audio plug connects to a cable that carries the audio signal from the audio playback device to the personal listening device. In order to provide high quality audio, such personal listening devices include speaker components that typically cover the entire ear or completely seal the ear canal. The personal listening device is designed to provide a good acoustic seal, thereby reducing audio signal leakage and improving the quality of the listener's experience, particularly with respect to bass response.
One drawback of the personal listening devices described above is that, because the devices form a good acoustic seal with the ear, the ability of the listener to hear environmental sound is substantially reduced. As a result, the listener may be unable to hear certain important sounds from the environment, such as the sound of an oncoming vehicle, human speech, or an alarm. These types of important sounds emanating from the environment are referred to herein as “priority” or “alert” signals, and each is typically characterized as an audio signal that is intermittent, acting as an interruption.
One solution to the above problem is to acoustically or electronically mix or combine environmental sound, including any alert signal present in the environmental sound, detected by one or more microphones with the entertainment signal. The listener is then able to hear both the entertainment signal and the environmental sound, including any alert signal. One drawback with such solutions, though, is that the alert signal may be unintelligible (or may even be inaudible) if the entertainment signal is too loud relative to the alert signal.
As the foregoing illustrates, more effective techniques for providing entertainment signals and alert signals to users of listening devices would be useful.